Determine the proportion of patients with HIV-related tuberculosis who have abnormal pharmacokinetics of isoniazid and rifabutin. Determine the risk factors for abnormal pharmacokinetic parameters and the occurrence of toxicity attributed to anti-tuberculosis therapy, evaluate the correlation between pharmacokinetic parameters of isoniazid and rifabutin and the efficacy of TB therapy, and define and correlate phenotypic INH acetylator status with the results of genotypic acetylator data obtained in the parent trial.